In my younger years I’ve joined Brainbech and did a few tests on it (during the different promotion periods when they were available for free). However I quickly discovered that these certifications have exactly the value of the paper they are written on (eg zero), because:

Any relatively seasoned IT pro can pass them, based just on what s/he heard and not having actually any proper experience with the subject. In fact it is often possible to learn during the test (!), and deduce the correct answers based on previous questions! To demonstrate this (and to brag a little ;-)), take a look at my certifications:

My actual capabilities are the following:

A lot of programming in many programming languages, including PHP. For example the only reasons for not being on the top for the PHP test is the fact that I didn’t know the answers from the top of my head to questions like what are the parameters for some weird LDAP function?, and because of this, even though I finished in less than half of the available time, I was still too slow.

A computer science degree.

Some networking experience, mostly hobby, with an unfinished CCNA.

Everybody can form the opinion about the matter, but my opinion is that I’m not qualified to work in fields like forensics, even though I got more than half of the questions right.

PS. I don’t mean to pick on BrainBench specifically, rather on the whole idea of online certifications. I talked about BrainBench, because it was the system I was most familiar with. I tried ExpertRatings, which seems to be an other big player in this area (they come up at place numero uno when searching for online certifications) with similar results.