I have this weird problem for some of my main keyword pages (mostly my 2nd tier pages thankfully). The pages will sit around the top 5 on page 1 for a day, then completely disappear for a day or 2, then come right back where they were before. This has happened for a while now (my site is about 9 months old, but I have really noticed it the past couple of months since I have really gained in the SERPs). Before I thought this was normal behavior and "getting out of the sandbox". The weird thing is that this does not happen on pages where I am targeting more difficult/ higher search volume keywords. They will just sit on the front page of Google and not move. But if the keywords are less difficult and lower search volume (sometimes I am the only person targeting this keyword), then this weird bouncing in the SERPs will most likely happen. I have tried things like lowering keyword density, making the posts longer, working on link building for the pages, etc. I have not used any PBNs or 3rd party SEO services. This has happened on money pages and informational only pages alike. I only monetize through affiliate links, no banner ads, etc. Any idea of what is going on?