So www.google.com is the domain name of google.
Each blog or website must have a domain name so that people may find it on the web.
By default you are given the option to select a free sub domain name for your blogger blog which typically ends at blogspot.com
www.islamicposts88.blogspot.com is an example of blogger blog domain.
There is no problem with bloggers blogspot.com domain but if you really want to adpot blogging as your profession then you should have a TLD domain.
The domain name which end at
.com
.org
.biz etc are called TLD or top level domains.If you want to use some TLD domain , you can register one from for 12 US dollars or equal amount to your local web hosting company
