Planet13 - 7:33 pm on Jul 17, 2013 (gmt 0)
"In my opinion the final results are hard to predict"
while I would agree strongly with the difficulty in predicting outcomes, if I were a betting man, I would be more inclined to view combining the sites into one as a positive move - at least nowadays.
It seems that "authority" has really been amped up in its value in the ranking algorithm. And one of the signs of authority - in my humble but often wrong opinion - appears to be the total number of links to a domain.
I think that in the past the "safe bet" was to be very niche oriented. there was a Matt Cutts video out there where he said if you were a small business, then try to rank for very niche (possibly localized) keywords. He said in effect that instead of trying to rank for (example) [field of medicine], you should instead try to rank for [City Name Field Of Medicine]
However, if you do a search nowadays for a specific city name combined with a specific field of medicine, then you will see BIG BRANDS at the top; the kinds that are basically directories of one kind or another that list medical practitioners from all the cities around the country.
Don't get me wrong: I am not saying that smaller sites don't have a chance. I am just surprised that larger nation-wide "directory style" sites still seem to be doing quite well.