hi if i post in dp with same signature, how much post is ideal for getting good ranking on particular keyword ?
Signature links from forums will not be sufficient by itself. You will have to to do some one way thematic link building. Forum signature links are usually low value (same as links from most social media site). As a thumb rule... the easier it is to get a link the lesser value it has.
For a popular keyword/phrase, you won't get an ideal ranking just doing forum posting. Sure maybe if you crank a few thousand out there you'll make a dent, but in the end you'll need more relevant links. What you do get from good forum posting is traffic, which is never a bad thing to have.
Signature links used to be a great source for your SERP some time back but latest algo gives little importance to these links, especially when it is from a single source (like more links from a forum). Let your links be from as varied source as possible, better if it is from a related niche and let it be one way, provided with a good anchor text...
i can only say the more postng, the better the SERP. However, the PR juice is not a good as blog commenting
I agree with the people above. Forum posting will rarely give you good rankings. SEO these days is all about varying your strategies and getting links from multiple sources. Really it's just good for getting your foot in the door. After that, your content and link building is what will get you the rankings.
Forums signature is not all that important again, you need link building for effective ranking. Good luck
The links in signatures are not important as they are not relevant to the page (generally) They would only count if someone just decided to visit the link in your signature, search engines hardly ever pick up on them unless your posts take up about 20% of all the other posts on the site.
Signature links alone are not sufficient to get good rankings. Concentrate on adding content and building quality links. But signature links from frequently crawled/indexed forums like DP can help by bringing search engines to the site and hence, better crawling and indexing.
but i get good approved backlinks from dp for my website so google gives more weightage compare to other links
It depends also on how much pagerank the page on the forum have. If there is no pagerank it work only for promotion, beside it's only from one website (one server). It's better to have different server/website to link to you rather than just one server.