Three things are required for any web site to become succesfull
content, Content, and MORE CONTENT
Google will index most web sites inside a week but can be up to a month at the outside after the site map has been submitted before you enter the listings. Not sure if you can map a forum but you probably can.
With over 10,000 results for mobile phone related forums chances are that you will be a long way down the rankings. Put simply your site is unlikely to show up in the first thee pages of search results for some time any potential visitor will be sidetracked by more established web sites long before they drill down to you.
What you need is an 'edge' , unique content that cannot be found elsewhere or something in the site appeals to a smaller niche group so Google will be to place your site before somebody elses because yours is more relevent to the search query. Then repeat the process for a different niche group.
For example, suppose I was running a search for Job Vacancies, I don't want to scroll through every job going on the planet I just want the ones that I'm qualified for and are nearby.
