If you link out to irrelevant sites, Google may ignore the page, too – but again, it depends on the site in question. Who you link to, or HOW you link to, REALLY DOES MATTER – I expect Google to use your linking practices as a potential means by which to classify your site. Affiliate sites, for example, don’t do well in Google these days without some good quality backlinks and higher quality pages.
Google, in many instances, would rather send long-tail search traffic, like users using mobile VOICE SEARCH, for instance, to high-quality pages ABOUT a concept/topic that explains relationships and connections between relevant sub-topics FIRST, rather than to only send that traffic to low-quality pages just because they have the exact phrase on the page.
What about other search engines that use them? Hang on while I submit my site to those 75,000 engines first [sarcasm!]. Yes, ten years ago early search engines liked looking at your meta-keywords. I’ve seen OPs in forums ponder which is the best way to write these tags – with commas, with spaces, limiting to how many characters. Forget about meta-keyword tags – they are a pointless waste of time and bandwidth.
Maintenance. Ongoing addition and modification of keywords and website content are necessary to continually improve search engine rankings so growth doesn’t stall or decline from neglect. You also want to review your link strategy and ensure that your inbound and outbound links are relevant to your business. A blog can provide you the necessary structure and ease of content addition that you need. Your hosting company can typically help you with the setup/installation of a blog.