Recently, I was trying to add my site to facebook, google plus and Pintest. I have notice that if I just add the link of my site, there's no image display and no description. Also, so here is few help links I think it would help you to develop your site to be more social.   meta tag templates  Thanks! This article was very helpful. Facebook Cache Looks like facebook have cache issue, I'm not sure how facebook will refresh it. Eventhough I set the image to my site, it was able to show at Google Plus but not from facebook.

few very useful seo tools and tools could improve your site's SEO.

When you see the error message "Crawl postponed because robots.txt was inaccessible" at your web master page. It is telling you that google can't crawl your site, something wrong with your robots.txt. That means, your site's SEO is dead, unless somebody know your site go to your site directly, otherwise google will not showing your site to search.

404 is normal Crawl Errors sometime show 404 because, you page is not exist anymore, or other website point to your page but your page is not exist, or you change the domain and change the folder of your url.

Angular with SEO, I think the answer is NO.  Angular just like other JS framework, dynamic loading content, these kind of imprementation is hard for SEO engine to catch up, it might have few ways for doing for the SEO. However, SEO is not simply if you put the html when page load, not just limit your link to 100 per page, not just put meta tag, Angular, or other JS framework to fully support SEO going to take a long time, or I don't know what going to happen next. So my anwser now is, angular is good for small app. That's it. Referenced following links.

Few information I want to share with my SEO Experience. I create a website, didn't do much work specific for SEO. However, I collect 50,000 data and lots of data are location specific. The website is not really ready. I had just put all the links to the page, for example the Home Page's link around 200, which I think in the SEO way, dont' put over 100.  Anyway, I was slowly improve my site. After around 1 month, one day, suddenly my site got around 1,000 visit from few cities. "Google found me", that's my first voice. however, my site didn't imprement well, it's down by that. While I was fixing my website, I have lost google's attenstion, my daily visit become zero again. After 10 days, google come back again, with 400 visit from one city. I'm guessing google slowly recognize this from one server to another server.  For me, I have to keep make my site better to let everyone to visit and not leave.

validatorW3 Use w3 validtor to check your page's html.

robots.txt Easiest improvement for robots is add file robots.txt and following content. It means allow any robots engine to crawl your site, and don't index your /keystone and /admin root folder.