I just found two bottles of unopened ketchup dating back several years. One says "Best used by September 19, 2008," and the other says "Best used by May 10, 2010." I think I should throw them both out, but I wonder if there is any chance they could be used in making a barbecue sauce which calls for boiling the ingredients together for 30 minutes. What about in baked beans or other such recipes which are baked? Would that kill botulism or other dangerous organisms?
Assuming that there are no apparent problems with it (either from storage method or upon opening and inspection), I am one to agree with StillTasty in this case and say that you would not likely encounter any problems making barbecue sauce. They say twelve months, though.
For the sauce though, not only will the long, slow boiling help; but the ketchup is likely chock full of high-fructose corn syrup (which acts as a preservative), and you will be suspending more sugar (again, a preservative) in it.
The rationale behind keeping most of these low acid sauces is that 1) the pH is low enough (below 4.5) - ie it is sufficiently acid - to prevent growth of food poisoning organisms such as botulinum, and 2) the product is pasteurised to remove temperature sensitive organisms that could survive at these low pHs. So, as long as the jar hasn't been opened, it should be safe, but the eating quality will deteriorate over time. If it has been opened and stored for more than the shelf-life says, other organisms may have got in, and if in any doubt I would chuck it. There is a history of reducing acidity in favour of increased consumer prefereeance of milder foods.