You could use the ID forum to ask the members to help you identify your 'weed'. Then you can make the decision whether to keep it or eradicate it.
with plantladylin - All Things Gardening Forum; perhaps you can start a thread there to talk about your weeds?
We sometimes forget that we have members in several countries, not just in the USA so the term 'weed' is subjective. While people in the US are busy trying to kill a plant others in Europe or Asia may consider that same plant a delicacy.