There are a ton of third party addons to SharePoint ranging from useful to just fun, from open source communities or commercial providers. The business value from the addon can be very good, but you need to make sure there are no hidden cost. What if the addon introduce:
One of the key questions you need to ask yourself is "What do I need to do to be able to support this?"
How your company handle third party addons and code must be described in your governance plan. With the governance plan you have a tool for mitigating the risks. If you don't care about the possible issues, so just write that in the governance plan (not a good idea though). The governance plan is unique for each company. Keep it short and follow up on what you decides on. Most of the value is in the work itself to create the governance plan.
Here are some guidelines and recommendations to help set up a plan for handling 3rd party addons in SharePoint:
In some cases the risk can be mitigated by running the third party addon in a separate farm (application farm). That way it will not negatively affect the other SharePoint solutions. An application farm has a cost, doesn't suite all 3rd party addons, and complicates worldwide/global installations.
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