I am researching a few Janssen families out of Ostfriesland as well. I
wonder if you have any of these in your database?

Frauke Janssen b. Feb 27 1844 in Ostfriesland, I don't know her parents
or the birthplace. She married Cornelius Weets before 1866 in
Ostfriesland, and I don't have that marriage date or place. They
immigrated to US c. 1893 and show in the 1910 Piatt Co, IL census. They
both died and buried in Monticello Cemetery, Piatt Co, IL. Him April 20
1912 and her April 28 1911. Their children were Katrina, Ed, Albert,
Anna Sophia, Jurgen "Jack", Cornelius JR, Aafka.

The second family was Martin Janssen b c. 1831 in Ostfriesland who
married a Teeske Unknown who was born June 5 1834 and died May 5 1909 in
Emden, Logan Co, Illinois. they were married before 1861 probably in
Emden, Ostfriesland, Germany.
Their issue incl Cornelius b. Feb 7 1861, Harmke Cornelia b. Nov 1 1864,
Eppe S b. Jan 13 1865, Ebelka Pancratius b. Oct 3, 1866, Berend S b. Feb
26 1869 and a female who married Mr. Harm Fink, birthdate unknown.

If you can help with any of these, I would be most grateful. My webpage
is at

http://worldconnect.rootsweb.com/~cindi_meyer/

and I hope you would find something interesting there,
happy hunting,
Cindi