Both quite amazing. (That they made it and that you found the article

)
It is quite a feat. It says thirty foot long but really that means a crepe thirty feet in diameter - nearly 707 square feet of evenly cooked dosa.
Of course, large dosas are novelty - more crisp than taste. 'Family' dosas or ones 10 to 12 feet long are available at some places (for 6 to 10 people usually). Pretty darn dramatic!