To answer the question: For this, it really doesn't matter other than it worries people. Unless, of course, you're using the same email/PW combination you use for your bank... Which you probably shouldn't.
An "insecure" connection means that someone could intercept data being sent between your computer and the forums *could* be intercepted by a nefarious 3rd party, as the data being sent isn't encrypted. Technically, even secure data could be intercepted.
An insecure connection to your bank or for financial transactions isn't good, but for a connection to this forum, it shouldn't matter. Unless the Russians want to take us over!