The Success of the site depends upon various many different Virtual things like Page Rank given by Google, Traffic Rank given by Alexa.com and the number of backlinks a website gets which depends upon the website. And there are websites that calculates all these things and  values the page according to them. What these tools do to you is that it estimates the success of the website and this will help you in providing the information whether a blog or site is going well or not. And even you can paste the code they provide on your website to make it attractive and. There are many ways to find out the value of the website.

1. WebsiteOutlook: This is the tool which I like the most. They not only provide the correct information about the backlinks and page rank but also tells us about how much daily pageviews your page got and how much you can earn with the website on a daily basis. It also tells correctly whether your website is submitted in Dmoz or not and the host I.P. of your website. And all this data will be updated every 15 days.
2. Cyberwyre : This website also predicts the value on the same basis but this website focuses on how much money it  can earn with different means like Text link Advertising, Affiliate Marketing etc.
3. CubeStat.com : This website focuses on deep website notes like meta info and meta tags on which basis their value.

There are many website like these which can be searched here. But these are the best one.