Bad neighbourhoods

Has the definition changed in the last 4 months?

[sullen]

Sorry if I'm repeating previous threads - I've been on maternity leave.

I have 3 sites which all seem to be suffering from some kind of penalty. The pages are still in Google, but they have been buried in the results for even quite specific terms.

Other sites seem unaffected and the only thing I can find in common between the 3 sites are a few link swaps. The linked-to sites are part of a group of subdomains (I counted 8 but there could be more) - could this be causing the problem?

[webnewton]

This could be a possible reason. There can be many more reasons though.
....as per my knowledge of the sites being penalised for linking to bad neighbourhood, these sites have been completly removed from the index. Yours' not...
Any other clue that you could provide.

[sullen]

The thing is, all the sites had goodish results before I went on leave (in January). Nothing has changed, so I'm assuming the algorhythm has changed. Well, of course I know it has, but I was wondering if anyone had noticed any changes specifically with bad neighbourhoods.

The sites are quite different in technical terms - one is almost all dynamic, one partly dynamic, one static. Plus there is some topic crossover in that "widgeteers" might find all of them interesting, but in different ways (hence they have this one link swap in common). They don't all link to each other, but site a links to sites b and c.