Rasputin - 5:30 am on Apr 8, 2012 (gmt 0)

How to know if a site has traffic throttling? I suspect our main site does, and that it operates 'hour by hour' rather than day by day (ie if one hour is high the next seems to 'correct' it), but I don't know how to calculate whether it is 'normal' or not.

For example, the same day of the week each week for the last 5 weeks, google source only, unique visitors:
week 1: 3468
week 2: 3492
week 3: 3433
week 4: 3538
week 5: 3544

Other sites we have don't show the same effect - but have less traffic so perhaps would naturally appear more random.
Traffic does vary by day of the week - sundays better than saturdays for example - but each saturday, sunday etc is consistent with the previous one.

Over the last year because of panda the whole site has been transformed - much improved articles, better template and layout, attempts to improve user and social engagement etc - but the numbers usually follow exactly the same pattern.
In analytics an 'hour by hour' comparison chart with the previous week shows they are exceptionally similar.

So question is, how to actually conclude that traffic resticting is taking place or whether this is normal?

Note: in all posts referring to 'wildly changing results' it would be useful to know approximately how many visitors the sites actually get each day and what levels of variance are being referred to etc