[kira-ee]

Hey,
maybe you can add a field "STEAM" in "Profile Information"?

Where people can write their STEAM_ID or STEAM_ID64, so it would be easier to find them, because there will be a button "STEAM" in every post (like PM/MSN etc...).

Or make something like a picture in my signature

[Butane]

like make it right under someones avatar or in the contact bar or something, good idea.

[Drunken F00l]

Unfortunately, the forum system I am using is not very extensible and I am making no plans to switch very soon.

[Sushimitzu]

I thought exactly that. It is annoying to search through all the person's posts to find that they never ever wrote down their Steam ID anywhere.