Signature links at the forums

[earnest]

Inbound on irrelevant sites will only give weight on your site.. You'll only have lesser chances to get higher PR..

Jeez, what kind of weight would that be then?

[Zukario]

My advice to popoloko is try to search a forum or post an articles that related to your sites niche, by doing this way you can built quality backlinks for your sites.

[MediaPrecision]

It doesn't matter if the forum is not one that is relative to your niche, but it does make a difference that the thread is relevant. Relevance is so important when it comes down to links.