why some sites are very slow online as well as they are unreachable

I like buxhost sites because it is light to my computer

There was a very big thunderstorm on the East Coast of the US which caused a massive loss of power and many servers went down, even though most have UPS systems. Many sites were affected, including MyLot, and it very likely also affected DNS servers and Internet routers. When a server goes down, it isn't just a matter of switching it on again and 'all is well'. Most servers run very complex database systems and, though many safeguards are built in so that data loss doesn't occur very often, it takes a considerable time to restore the systems to proper and smooth running. DNS servers (the machines which translate human-readable URLs like http://www.mylot.com into the string of numbers (called IP addresses) which computers understand are networked together and if one or two go down, all the routes by which your access to sites have to be recalculated and, when the servers come online again, they have to update all their records to take account of the time they were offline. Denial of Service (and Distributed Denial of Service) attacks are something quite different and you should not confuse them with 'Acts of God'!

Perhaps they have problems with the servers, as you know mylot also experienced the same problem because their server were outraged due to big storm that happened in east coasts. Here is mylot’s notification regarding the downtime, and probably the sites that you visited got the same problem like this. Our servers are hosted with Amazon EC2, and a huge thunderstorm on the East Coast of the USA knocked out power everywhere, including one of our EC2 datacenters. As a result a huge number of websites around the internet faced outages. so it is not because ddos attack but because their servers was down because of the storm. hope everything is going back to normal soon.