Tier 2 is to gradully turn your tier one sites into "mini authorities" themselves.
When first made (no matter where you make them) tier one sites are always underpowered (or zero powered)
Tier 2 boosts these and in turn your money pages.
Tier 3 is almost exclusively JUST to index your tier 2
You need expotentially more content and linking sites the further you go out (roll down the pyramid)
If you have an authority site then really invest in tier one and automate ot outsource the rest (unless you want to work 80 hours a week linking them up)
Most of my tier ones are self made - all of the other stuff is automated and this process works REALLY well.
I would outsource more but with several hundred tier ones to power up their are zero products here on BHW or anywhere else that are any frikking good at doing this. Likewise never found a service that creates tier ones very well at all. (I'd go further and say of the many may I've tried they are really (REALLY) poor. Provide a quick boost - but are content thin, badly created and often more of a hinderance. The biggest issue is just how weak the content provided is. 9 out of 10 provide one post on an unaltered profile (with littlee or no detail and no customization) and this content is really pi$$ poor. Low word count, spammy, uninteresting and often plagirised.
A good tier one is a quality site that provides CLICK THROUGH not just link juice.
Every one I've seen created by a SEO service has been total crap - only a dunce would consider clicking through the garbage
So I create my own tier one and use auitomation for tier 2 and 3 (and to add a few new or "disposable" tier one links from time to time)
While we are on this - let's remember that Google couldn't give a f&ck about copyscape - it's not something they use and it doesn't use a method of measuring uniqueness that they use - it's basically a waste of time - a placebo for noobs to think they have bought some "Google immunity" when in fact it means nothing of the sort.
"90% copyscape pass" might as well say "Free banana with every post" for all the difference it makes to SEO
Uniqueness is increasingly important - the way copyscape measures it isn't.
There are some experts here on BHW who will tell you all about uniqueness and how to do it PROPERLY (Madoctopus is one)
Scritty