about:blank & about:tabs are internal to many browsers.
Some malware 'locks' the home page to display about:blank, but the blank page home page is not malicious in itself.
From Cliff's link:
About:Blank is normally used as an internal scheme that instructs the web browser to display a blank HTML page. It is often used by programmers as an initial state for opening browser contexts, or the user can set the browser startpage to about:blank to display a blank page when starting their browser.
An About:Blank home page hijacking occurs when a malicious program hijacks the browser homepage (aka startpage) so that the user cannot reset it, and displays about:blank in the address window.
If you are unable to change the homepage using normal procedures (Tools>Internet Options) it is likely you have a malware infection of some kind.
Some sites try to sell scareware (usually some bad malware removal utility).
IE has (or had) an option to explicitly set the home page to a blank page (about:blank) - now why would Microsoft do that if it were malware
Anyway, it is completely safe to set your home page to about:blank ... if you're concerned about possible malware, try about:tabs instead. Using a non web home page significantly decreases the time your browser finishes loading. You can also use local HTML
Not a big deal, most people don't hang out on their home page, they go to some other site.
The thing about home pages is: it can be anything you want.
The issue I have with 'standard' home pages is: they load a lot of crap.