I have had two WordPress blogs hacked into previously. That was at a time when I was doing almost no online marketing, and until I found time to deal with the situation (weeks later), these sites were penalized at the major search engines. They weren't eliminated the evaluations were reduced.
By default, the latest version of WordPress is pretty darn secure. The development team of WordPress has considered anything which may have been added to some fix wordpress malware plugin plugins. Before, WordPress did have holes but now most of them are filled up.
Should your site's server go down for will proceed with it. You will make no sales, get no traffic or signups to your site, until you get the website and in short, you're out of business.
Fortunately, keeping your WordPress website up-to-date is one of the easiest things you can do. For the past couple of versions, the ability to set up updates has been included by WordPress. A new upgrade becomes available.
Black and whitelists phrases based on which area they look within, in a page request. (unknown/numeric parameters vs. known post bodies, comment bodies, you can try here etc.).
Always bear in mind that the security of your blogs depend on how you handle them. Make sure that you follow these tips to avoid exploits and hacks on sites and your own blogs.