i have a website which ranks in google for 4-10 days at a time, every few months. this has been going on for 2 years now. someone theorized that it must be a time when google was doing a bigger than usual update to their algo and during that time some filter is taken off, but once the dance is over the filter goes back on. anyone else experience this? how do i find out what this filter is?
here are some recent dates:
aug 20-29
may 12- june 14 (this one was unusually long)
march 9-17
jan 4-7
nov 5-7
sept 5-8
normally the site gets about 300 organic google visitors. during the above periods, this jumps to 1000-1500 only to drop precipitously back to 300
thanks