SEO experts love to measure. They measure traffic, PageRank and rankings for they need something to follow. Moving on, there is still a lot to determine further usability metrics or strict business. SEO still makes sense in various other aspects, especially with links your webpage get which still determine above all your success in Google search.

Number of Backlinks
You still need to know how many people or rather pages link to you. especially if this week more or less do it. The sheer number may be meaningless if you have 10 links from one site though. So focus also on domain popularity (links from one domain counted as one). For instance, [link:www.cardekho.com/usedCars] will list webpages that have links pointing to the Used Cars in India page and [link:www.cardekho.com/carmodels/Maruti/Maruti_Alto] will list all links pointing to Maruti Alto page and in the same way [link:www.cardekho.com/carmodels/Tata/Tata_Nano] will list all links pointing to Tata Nano page.

Quality of Backlinks
Getting a ton of links may mean nothing in comparison to one link from high page rank webpage. So determine the quality of links: Has the linking page many other outgoing links? Has it PageRank? It it an old authority domain etc.?

Google cache date
Many SEO specialists resort to checking the cache date in Google (Google saves most pages in a “cache”) for determining the quality and success of a website in Google. If the cache date is older than one month the site is either dead (no fresh content) or has a very low authority with Google. Of course you always should check whether a site has a cache at all. Not cached sites probably get de-indexed (penalized) by Google. For instance, [cache:www.myjewelrydeals.com] will show Google's cache of the Silver Jewelry - MyJewelryDeals homepage.

Google bot visit frequency
Your cache might be one week old, but if Google bot visits daily it’s OK in most cases. You can check with most server side web analytics solutions.

Last time Google bot visited
This is almost the same as above but only almost. If you have a new content page and the bot visited yesterday and you’re still not in the Google index something might be wrong (like duplicate content problems)

Pages indexed
It’s seldom as simple as “the more pages indexed the better” but for small sites it often is. If you have 50 pages online but only 20 indexed your site is not successfully spidered by Google. A site for mobile plans [site:yourbillbuddy.com] search in Google at present shows 265 indexed pages for YourBillBuddy.com.

PageRank
While I would like to stress that watching the toolbar PageRank does not matter much nowadays anymore you certainly want to take a look at the pass rate of PageRank. Google PageRank is passed via the links on your site. A home page with PR 5 should have subpages with PR 4 or at least 3, otherwise you have too many links or your internal link structure is broken.
For instance, at present Page Rank for website New Cars in India - CarDekho.com has Page Rank - 4 and one of its subpage for Maruti Alto LX stands for Page Rank - 2.

Alexa Rank
While Alexa is not really reliable. Even traffic estimates of Alexa can be compared to other sites, other time periods (more or less traffic this year than last?) and to other traffic estimation tools. Know more about Alexa Ranks in the previous reads.

Compete Rank
While Compete is said to be more reliable than Alexa it only is for US traffic. This is both good and bad news but at the same time allows, e.g. compared with Alexa, to see where you’re heading. If you server the US market, take a close look at Compete.