I read SLs using SL Genie as my tool/browser of choice and I do not feel it matters how many credits for reading. I find that under normal use I see the same ad repeated over and over again. I do go beyond the level of just collecting credits but only if the promo peeks my interest, I think the key is getting the promos out and making them as interesting as possible then the promos will be selected more often. Basically we are in an environment where numbers are more important then the value of what we read. We can collect the credits and use them. I use both big and small SLs and try to get lots of credits so I can put out lots of promos, If I have to buy then so be it, at least some will read these and maybe react to them.