Sorry if it is a obvious question. If I am going to start a site but wait a couple of months or so for traffic to pickup before reaching to advertisers, do I need to form a LLC right away? My site will not sell any products, it is user submitted only so no cart, etc. But I will hopefully turn a profit on advertisers soon. Should I wait to form? Or do I even have to? I want this to be legal, so nothing pops up and the IRS is at my door. Also should I worry about copywriting my logo, etc?
You never need an LLC to run a business; unless you want one. You may run your business as a “sole proprietorship”. Remember to keep track of your business expenses so that you may deduct them from your income for tax purposes.
When asking a question like this, you really ought to state which country (or other jurisdiction) you are in, as the law varies considerably from place to place.
You mentioned the IRS, which suggests you are in the US - but that’s only a guess on my part.