If there is no alt tag, search engine doesn't understand anything from the image.
That's why you should use alt tag on your all pictures, which you use in your website.
Alexa rank is a scoring framework that measuring an activity and making characterization as per this movement those Alexa Toolbar clients are going to sites.
Information : Page Speed is the speed at which your site responds to commands input.
You can create links by adding rel="nofollow" tag, which is not searched by search engines. You also should add nofollow tag to the links, you think it doesn't need it.
On the off chance that you have site that have high fame, both you are gone to by more guest and you pick up high benefit on promotions that you show.