Ok, so how do you get started being "everywhere"?
First Step
First, pick out 6 or so top forums in your niche.
Join those forums and start really, truly, genuinely participating in those forums.
Don't spam in your signature line - a simple link to your site is plenty.
Trust me, when you share good content out in your community or really help someone, they WILL go looking for more info/help from you.
Second Step
Second, pick about 6 or so top blogs in your niche - those of the true "market leaders" or news sites that the people in your niche follow and read (and link to for answers when helping in the forums with niche-related questions).
If you're really interested in the topic of your niche, you probably already know the sites YOU like to read regarding your niche, right?
Once you've established those sites, follow those sites - participate and further the conversation/topic of their posts via your comments.
If someone asks a question in the comments area and you feel confident in your answer - rely to that question and help the blog owner by helping his/her readers (we like that).
Above all -
DO NOT SPAM THE COMMENTS
Spamming via comments is a great way to get those bloggers to hate on you and NEVER link to you or recommend you.
Don't use a keyword as your name in these comments and do not link to your site from within your comment either.
That's just tacky.
Use your real name or, like I did, pick a nickname that is unique (or in my case, downright silly and weird...lol)
Be real.
Be the comments you want left on YOUR site.
Third Step
Keep doing this.
It's a beautiful cycle of participating in your niche community, knowing the things people are talking about and want to know, creating content on your own site about those topics/questions...going back and participating some more.....people read your forum posts and comments, click thru to your site and find a wealth of info about the things they really want to know.
They Tweet you, Like you, share your stuff, link to you.....then one day, they might linking to YOUR content inside those same forums and blogs.
Rinse and repeat.