Title:  Title is the Heading  of an ad. This is very important. The visitors normally see only this title on the listing page. Recommended maximum length of title is 70 characters.

Description : Description means Body of an ad. This is details of your offer. Here you should describe your product or service clearly. But don’t use too long description. Use HTML and image where possible.

Campaign: Campaign means an whole advertising plan. A campaign may consists of multiple ads posted on multiple classified sites and locations. The purpose of a campaign is to promote one or several related products or services.

Live ad:  A classified posting which is available to the visitors of that particular site is termed as a Live Ad or Live Posting.

Flagged ad: An objectionable ad posting which is removed from the site as it was flagged as spam or otherwise objectionabale by some visitors. Over posting flames flagging. So avoid over posting.

Ghosted ad: Some sites like craigslist, backpage, kijiji, gumtree removes some postings with notifying the poster. This is normally done by some kind of software automatically. This doesn’t require flagging by visitor. A post even may not appear on the site at all. Posting with non-local IP is a major reason of ghosting.

PVA: This term relates to craigslist posting.  To post under service categories of USA or Canada craigslist an account verified with a phone number is required. Such account is called PVA i.e Phone Verified Account.

IP Address: Each computer is identified with an IP Address. The free classifieds sites use this IP address to prevent excessive posting by the same poster. Location may be determined from IP address. Most of the popular sites use this information to prevent posting by foreigners.

URL Cloacking: Hiding a long URL with a short redirect URL is called URL claocking. This is required if you are trying to promote your affiliate products on online free calssified websites.  Free URL shortening services may be used for this purpose.

• Gumtree Australia  is the most populasr local free classifieds of Australia. Current Alexa rank is 4,576 and Rank amoung Australian sites is 57.  Popular cities of Australian Gumtree are sydney.gumtree.com.au, melbourne.gumtree.com.au, newcastle.gumtree.com.au, perth.gumtree.com.au, brisbane.gumtree.com.au. 
• Craigslist.com.au is the second most popular free classified website in Australia.  Current Alexa rank is 28,973 and Rank amoung Australian sites is 748.  Popular cities of Australian Craigslist are sydney.craigslist.com.au, melbourne.craigslist.com.au, darwin.craigslist.com.au, brisbane.craigslist.com.au, canberra.craigslist.com.au 
• cracker.com.au  is another free classifieds for Australia. Place an Advert on cracker now
• adoos.com.au  Australia Free Classifieds. Post your FREE Ad on Adoos.
• locanto.com.au  Browsing, searching and posting classified ads on Locanto Australia is fast, simple and free. Posted ads will be live for 60 days,  pictures may be used and on Locanto you can even add a clickable hyperlink url to your website.
• aufreeads.com Also popular in India and Saudi Arabia.  Post a Free Classified ad at this Australian classifieds website for FREE! No sign up. No email confirmation. Your ad goes online immediately.
• kugli.com Kugli is getting popularity in Australia too. Kugli is already popular in India and Pakistan.
• adpost.com  Australia free Classifieds for over 1000+ cities, 500+ regions worldwide & across Australia.  Post a Free Ad with video.
• freead.com.au Australian free advertising portal.  Register for free!
• ozfreeonline.com Oz Free Classifieds Online is the largest free Australian advert posting site. Place your classified ads, items for sale, wanted to buy sell trade online. Get free classified ads listed in Perth, Sydney, Melbourne, Adelaide, Brisbane, Queensland and other cities in Australia. OZ free Online has Auction section as well.
• dclassifieds.com.au  Place FREE classifieds ads on dclassifieds  which will be seen by hundred of thousands of australian internet shoppers.  Place Your Ad on dcclassifieds
• annonz.net Your free local classifieds ads in Australia.   register on annonz  for free advert today!
• quokka.com.au  online version of Quokka Free Ad Paper. Quokka was founded by Erik and his wife Elizabeth. It is published every Thursday.
• Other sites are following:

www.hukes.com

www.olxaustralia.com

www.ablewise.com/ads/listings/Australia

elist.com.au

yousell.com.au

oznet.net/classiads

dewalist.com

perthonline.net

classifiedshere.com.au

hotfrog.com.au

australiaclassifieds.net

tradingpost.com.au

simpletrade.com.au

Following is a list of Free Video Classifieds I have found so far:

• http://www.adhysteria.com/   Popular in India, United States, Australia, Canada and Philippines. adhysteria.com has a Alexa rank of 65,355. So it’s quite popular.
• http://www.iposte.org/  -  It’s a new site. Getting popularity in the United States and Puerto Rico
• http://www.myplace2sell.com/
• http://www.listasaurus.com/  This free video classifieds is being popular in the USA and Thailand.
• http://www.reachoo.com/
• http://www.realpeoplerealstuff.com/  Popular in the United States, India, United Kingdom, France and the Philippines

Most of free video classified sites are new. But they are gaining attention and popularity day by day. Hopefully, a lot of new free video classifeds will appear soon.

Following is a country-wise list of popular online free classifieds:

• USA: craigslist.org, kijiji.com, backpage.com .  More free calssifieds of USA.
• Canada:  craigslist.ca, kijiji.ca, Classifieds.Ca . More Canadian free classifieds.
• UK: gumtree.com, craigslist.co.uk, adzooks.co.uk, adoos.co.uk. More free classifieds on UK.
• Australia classifieds: gumtree.com.au, craigslsit.com.au, ozfreeonline.com
• India classified ad posting: quikr.com, craigslsit.co.in, kugli.com, webcosmo.com, locanto.com, vivastreet.co.in, olx.in
• Japan classified advertising: kijiji.co.jp, craigslist.jp
• Spain local classified websites: loquo.com, spain.franglo.com,
• New Zeland classified websites: gumtree.co.nz, auckland.craigslist.org
• Singapore free online classified sites: www.gumtree.sg, craigslist.com.sg, olxsg.com
• Italy classified advertising:  www.kijiji.it, italy.franglo.com, italyclassifieds.net
• French local classifieds: www.kijiji.fr, frenchclassified.com, paris.franglo.com
• Germany classifieds: kijiji.de, locanto.com
• South Africa classified sites: gumtree.co.za, orangepages.co.za, youpost.co.za
• China online classifieds : baixing.com,  shanghai.craigslist.com.cn, www.locanto.cn
• Philippines free classifieds:  manila.craigslist.com.ph, classifiedsph.com
• Russia : www.slando.ru, ru.anuncioo.com
• Poland : www.gumtree.pl
• Hong Kong:  gumtree.com.hk, hongkong.craigslist.org
• Thailand: craigslist.co.th
• The Netherlands: www.marktplaats.nl, amsterdam.craigslist.org
• Mexico: craigslist.com.mx, www.mexonline.com, mexico.zeezo.com
• Brazil: rio.en.craigslist.org, redeparede.com, brazzilads.com
• Argentina: buenosaires.en.craigslist.org,
• Switzerland : zurich.en.craigslist.ch, market.local.ch/en, www.kijiji.ch
• Belgium: www.kijiji.be
• Austria: kijiji.at
• Czech Republic: www.slando.cz
• Slovakia: www.slando.sk
• Hungary: www.slando.hu
• Ukraine: www.slando.com.ua
• Turkey: www.kijiji.com.tr, www.turkeyclassifieds.com
• Taiwan: www.kijiji.com.tw, tw.anuncioo.com

Feel free to share popular free classifieds of other countries here.

1. kijiji.ca : In Canada Kijiji is as popular as craigslist. In some cities kijiji is even more popular than craigslist. Kijiji has many more Canadian cities on it’s list than craigslist.ca
2. backpage.com : Although very popular in USA, backpage has only a few Canadian cities: Toronto, Vancouver, Montreal
3. Red Leaf Ads: New but nice free ad site. Try it.
4. http://www.adpost.com/ca/
5. Tradepoint : Tradepoint is Canada’s free online classifieds network for used autos, cars, used trucks, boats, computers, Canadian real estate, antiques, furniture, electronics and much more.
6. Oodle free classifieds : free classified site as well as free classified search engine.
7. http://www.cdncc.com/
8. Classifieds.Ca a premiere free classifieds ad network of Canada
9. Adoos Canada
10. Canadaclassify.com Canadian Online Local Classifieds Service
11. BuyAndSell.Canada - Canada’s National Free Classified Ad Network.
12. btcanada.com – Free Ads – Canada Free Classifieds
13. OLX Canada
14. http://www.sellitbuyit.ca/
15. http://www.classified.ca/
16. Canada’s bargain city
17. Kugli local classifieds
18. Hoobly free local online classified site.
19. Locanto Free Canadian Classified Ads.
20. Post an AD is a FREE Online Classifieds Website for Canada.

Most of the free classifieds sites including craigslist.org and backpage.com allow hyperlink to other website in ad description. So getting one-way backlink from free classifieds advertising is quite possible. The problem is that those backlinks aren’t permanent. Each post has a certain life span ranging from 7 days to 6 months (popular sites have lower life span while new sites have longer life span for the postigns). Postings will expire after that time and the link will no longer exist. So one time posting will not be of much help in the long run. In case of continuous  posting on a weekly or monthly schedule, search engines will always see some backlinks from those sites and will index those pages. So to get benefit from free classifieds sites for SEO, continuous ad posting is required.

Some sites like vivastreet.co.uk allows to reposting and the URL of the original post doesn’t change upon reposting. In such cases getting almost permanent link is possible provided the ad is renewed regularly.

Another option of SEO is also available. Although it is also transient  in nature, sometimes  it is highy effective. It is possible to post an ad whose body is filled up with targeted keywords in high density. Search engines like google picks the posting pages from popular free classifieds sites like craigslist within 24 hours (even earlier). And postings on craigslist and other popular free classifieds get very high position on SERP. So it is possible to reach google first page for some specific keywords within very short time with this method. But when the ad is expired, you loose everything.
Finally, it can be summarized that ad posting on free classifieds may be helpful in SEO but primary purpose of free classified advertising is not SEO. Getting targeted traffic quickly is the main purpose of free classified advertising.