[stigmata]

Depends on villain.

In some circumstances (e.g. Mr. Uber Passive) it's OK to fold.

With the state of online poker, you have easy odds to call at least the turn. The turn checkriase could be a set or 2 pair but also likely to be Jx, Tx, even a straight or flush draw sometimes. Against this hand range you have odds to call the turn and hit top pair or the gutshot.

The more difficult question is whether to call a blank river or not, which is obviously opponent/image specific.

The problem stems from the normal criticism of MLH: It advocates folding to turn check-raises far too often. This appears to stem from the fact that it was written for historic weak-tight live games where turn check raises really did mean "I can beat top pair". With the ultra-aggressive and fancy state of online games, a different play is often correct.

However, I do think MLH is a great book, and still does a great job of highlighting certain situations that you really should be folding. You just have to keep the different table dynamics in mind.