Every business should be cognizant of their website's search engine optimization efforts, and I highly recommend following SEO best practices in order to set your site up for search success; but did you know that your site can actually be over-optimized?
It's an unfortunate mistake that often happens when a company unknowingly signs on with a black-hat SEO firm. You'll quickly see a large leap in traffic and results, but then a month or two later, are officially blacklisted by the Google guys, and nowhere to be seen in organic search results. When this happens, it's because the actions taken by the SEO firm are construed as trying to play the system. There's a very high priority from search engine companies that their rankings be natural and good quality, so they've concocted the latest formulas and algorithms to wipe out the bad behavior.
Fortunately, there are some ways to tell if SEO tactics will eventually lead to harm, so take some time to go over these key areas:
First, look for Webmaster warnings
Right off the bat, you should be able to see if you're already up for, or experiencing a manual action from Google.
"While Google relies on algorithms to evaluate and constantly improve search quality, we're also willing to take manual action on sites that use spammy techniques, such as demoting them or even removing them from our search results altogether." - Matt Cutts
To access this information, log into your Google Webmaster account, then click Search Traffic > Manual Actions. If a web spam action has been applied to your website, the action will be listed, and there will be links to resources that will help you fix the issue.
Check for black-hat link building
Using the referral tool in your CMS, or a third party partner such as Moz's Open Site Explorer or Google Webmaster's "Links to your site", take a look at the inbound links leading to your domain. If you're using Moz, you'll be able to see the domain authority of these sites in the right-hand column - pay close attention to links with a domain authority of 15 or less, or for the quality of the website. If you're seeing a large percentage of your links coming from low authority domains, this may be considered spammy, and in-turn be penalized.
What is the anchor text for these links?
After looking at the quality of your inbound links, you'll next want to check the anchor text being used on the external site. Way back in the time of buying CDs and flip phones, using optimized anchor text was the thing to do to boost rankings. Essentially, you would choose a keyword, then you would pay to get other websites to link back to you using that exact phrase.
Of course, search engine companies caught wind of this tactic, and have altered their algorithms to discourage this behavior. Unfortunately, there are still many companies that continue to employ this technique, and have suffered the consequences. Aside from your brand name and URL, look for large percentages of an exact term being used to link back to your site using Moz or Webmasters. If you're looking at percentages of 40% or more, you may want to do some further digging to check on the quality of links as discussed above.
Unnatural body copy, alt tags, meta data, title tags, etc.
Ok, now do you remember your Blockbuster card, AIM account and perhaps even the frosted tips you were sporting? Yeah, we're going back again. Well, during that time, it was also "trendy" to obliterate site pages with keyword stuffing.
Again, this tactic has since been frowned upon and actively penalized by search companies, but there are always black-hatters looking for a quick win, unfazed by the detrimental free fall after a penalty has occurred. If you're seeing a term or phrase being repeated over and over again unnaturally in your body copy, this is the cue for red flags.
To be safe, also pull a list of your site's metadata - again, look for anything that seems unnatural or repetitive. Even though it's still very important to focus on a keyword and optimize key areas for that keyword, stuffing will never again be recommended approach to ranking well for an extended period of time.
Incorrect tracking, not filtering IPs
This last portion won't affect your rankings, but will certainly affect incoming data from your efforts. In Google Analytics, and likely your CMS platform as well, you have the opportunity to filter out traffic by IP address - depending on the goals from your analytics data, you may want to filter out traffic from the IP of your office space, or of the agency you are working with. Internal search may cause skewed spikes in traffic that may not be qualified or relevant to your goals.
Some black-hat agencies will use these spikes as evidence that their efforts are paying off - don't let inaccurate interpretations of accurate data throw you off. Check your settings to ensure that irrelevant IPs are being filtered properly.