Currently I own one forum with average 15-25 users online !! and almost 350 threads and more then 1k+ posts.. I like godaddy services but could you let me know that is godaddy able to hold my site with 4GH ultimate plan ? default forum software is phpbb right now, but we are thinking to move on mybb or vbulletin later on. Or let me know that how much php memory limit does godaddy provider by default ?
With 15-25 Users in average online, i would strongly suggest you to seek a proven and quality shared hosting provider
I would receommend getting a VPS server as your growth is going to outgrow the shared environment. Not too mention the security a VPS will provide along with your own dedicated resources. Plus I agree 100% go with a proven hosting company, not a company that is a domain registrar doing hosting on the side.
Don't go with GoDaddy, this is because they 're domain registra. You can't get support with them as well as other hosting provider.