I'd love it if I was still alive and we got in contact with ET, would be very scary though, I reckon there's 1000s of different earths harbouring life out there.
I wouldn't say thousands, i'd say billions.
Here's the maths.
The sun is a star, orbiting the sun are 8 planets, and some 6 dwarf planets.
The nearest star is 4 light years away in our galaxy. Our galaxy consists of about 200 to 400 BILLION stars (suns), the nearest galaxy is 2.5 million light years away (that's 14 686 504 184 000 000 000 miles) it is estimated there are a TRILLION stars (suns) in that galaxy.
In the OBSERVABLE universe, it is estimated that there are 500 BILLION galaxies. The furthest observable galaxy we have seen was in the Hubble Deep Space Field picture - the galaxies in that picture are 13.7 BILLION light years away (that's 804820429260000000000000000000000000 miles) - so that's 300,000,000,000,000,000,000,000 stars - that's 300 sextillion.
Concept of scale for you:
Alone? Nope. Other intelligent life? Definitely!