How many incoming links per anchor text is allowed per day without setting off Google red flags? is 30/day too much? Also -- how does Google know the difference between a link directory vs. paid link sites?
google likes "natural", so try to keep your link building as natural as possible. that said, 30 links/day sounds much more natural than say a 1000. of course quality counts. i'm not so sure whether google cares about paid vs. free directories, but i'm sure it cares about good v. bad directories. so if you do decide to submit to directories make sure your submissions will not be part of a bad neighborhood. submit to good quality directories that don't let every site in.
30/day would not be too much. keep in mind that not all the page where you submit your links will be indexed by google in the same manner as you submit. however, you havre to keep building links. if you start a site and build few hundred backlinks and then stop, it will not look natural to SEs
Well, It depend on you site age if you have old site then you can get link as much as possible but if you have new sites then you have to very careful about this. and I want to mention one more thing here if you are getting 30 links a day then you need to continue in future also if you'll decrease number of links a day then it can effect on your site ranking